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Depression is a major public health problem that is growing worldwide. The causes are complex and vary from person to person. However, new research estimates that up to one in five cases of depression among older adults could be prevented by reducing loneliness. The study therefore has important public health implications, highlighting the need for comprehensive action across society to combat loneliness. 

This is the first large, long-term study to investigate the link between loneliness and depression in people aged 50 or older. It confirms that feeling lonely is associated with an increased risk of future depression. The link exists irrespective of other related social experiences and exists even among people who are not socially isolated or who feel socially supported. After experiencing loneliness, the risk of depression persists for up to 12 years.

Loneliness can be changed or controlled, unlike other risk factors for depression, such as our genes. But previous studies looking at the relationship between loneliness and depression have so far been inconclusive.

This research supports the implementation of the Government’s strategy for tackling loneliness in England, which launched in 2018 and has become particularly relevant following lockdowns and social distancing during the pandemic.  

What’s the issue?

Depression among older adults is common, affecting four to nine out of every 100 people worldwide. Recent data suggest that these figures are increasing. Depression is associated with other conditions and in severe cases, can be life-threatening because it can lead to suicidal feelings.

Understanding the causes could help to identify people most at risk and inform strategies for prevention at a population level.

One in three people aged 50 years and over in the UK report feeling lonely. It may partly be due to retirement, bereavement, reduced social networks and physical and cognitive decline. Loneliness is a painful emotional experience that occurs when a person’s social relationships do not fulfil their needs. It can be related to, but distinct from, other aspects of relationships such as social isolation and social support. 

Previous research has investigated the relationship between loneliness and depression, but has not been conclusive. For example, many studies did not follow people for more than two to three years – and few adjusted for other potential causes of depression such as genetics.

An improved understanding of the impact of loneliness on mental health could lead to new interventions to help prevent or reduce the burden of depression in older adults. 

What’s new?

In this study, the researchers analysed data on 4,211 people included in the English Longitudinal Study of Ageing (ELSA). They were all aged 50 and above. Two-thirds (2785 or 66%) were unemployed or retired. 

Participants had answered questions every two years for 12 years. They had described their experiences of loneliness, social engagement and social support, as well as symptoms of depression.

Their answers to questions about lacking companionship, feeling left out, and feeling isolated were combined into a loneliness score on a seven-point scale. The results were adjusted to take account of social experiences (such as perceived social support). and other factors such as age, sex, marital status, mobility, education and wealth.

The higher the loneliness score, the more severe the symptoms of depression. The researchers found that:

    • each one-point increase on the loneliness scale was linked with a 16% increase in average depressive symptom severity score
    • loneliness was linked to nearly one in five (18%) cases of depression one year later
    • the effect of loneliness decreased with time but was still associated with one in ten (11%) cases after 12 years 
    • depressive symptoms increased over time among people with greater loneliness scores, indicating that loneliness was causing future depression.

The researchers had taken account of depression and loneliness at the start of the study. This reduces the possibility that depression was leading to loneliness. They concluded that it was the other way round, and that loneliness was increasing the risk of depression.

Why is this important?

The researchers discuss how loneliness might impact on mental health. It could be that people who are lonely are extra-vigilant in social settings and anticipate rejection. They may disproportionately recall negative social memories and develop negative beliefs about themselves. Ways of thinking like this are associated with depression. 

The results suggest that tackling loneliness has the potential to reduce or even prevent future depressive symptoms among adults aged 50 or over. 

Health professionals working with older people who report feeling lonely should be aware that they have an increased risk of depression. They may need interventions to reduce loneliness to support their mental health. Psychological therapies have been shown to reduce loneliness, especially those that target ways of thinking.

Interventions could include:

    • social prescribing (a link worker takes a holistic view of someone's health and wellbeing and gives people time to focus on what matters to them)
    • psychological therapies that target negative feelings of loneliness
    • social skills training 
    • psychoeducation (teaching specific skills to improve mental health such as problem-solving and other forms of coping, good sleeping habits and collaborative working)
    • supported socialisation (offering people support and guidance to select and attend activities).

Community-based approaches designed to reduce loneliness could be an effective way to prevent or reduce depressive symptoms in older adults. These interventions might involve building community resources, strengthening networks within neighbourhoods, community connectors in primary care, or arts and sports-based approaches embedded in communities. Improving the quality of relationships and increasing companionship, meaningful connections, and providing a sense of belonging, should be a key part of these strategies. It is not sufficient just to increase the time spent with others.

What’s next?

The next steps will involve increasing awareness about the link between loneliness and depressive symptoms in older adults - and influencing health and social care guidelines to reduce loneliness in the community. 

The people included in this study are all White British. Further research could explore the effect of loneliness in more diverse populations. Research is also needed to evaluate the effectiveness of specific interventions designed to combat loneliness among older people. 

You may be interested to read

The full paper: Lee SL, and others. The association between loneliness and depressive symptoms among adults aged 50 years and older: a 12-year population-based cohort study. The Lancet Psychiatry 2021;8:1 

A Connected Society: A strategy for tackling loneliness - a  policy paper setting out the Government’s approach to tackling loneliness in England.  

The Campaign to End Loneliness gives information on loneliness.  

The NHS website gives information on depression

Funding: The English Longitudinal Study of Ageing (ELSA) is funded by the NIHR. This research was supported by the NIHR University College London Hospitals Biomedical Research Centre.

Conflicts of Interest: The study authors declare no conflicts of interest.

Disclaimer: NIHR Alerts are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that views expressed in NIHR Alerts are those of the author(s) and reviewer(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

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